A. Field of the Invention
The invention relates to a protective fabric having a high resistance to penetration by instruments such as ice picks and the like, and to vestments made from such fabric.
B. Prior Art
Protective clothing is used in a multiplicity of applications to protect the wearer against harm from a variety of objects such as knives, picks, bullets, and the like.
Protective clothing of the type worn by prison guards, among others, must be capable of withstanding assault by a variety of instruments. Typically, they are judged by their resistance to ballistic penetration (e.g., by 0.357 magnum and 9 mm ammunition); dagger cutting; penetration by single and double-edged knives; and puncture by both blunt (e.g., 3:1 ratio of tip diameter to shaft diameter) and sharp (e.g., 12:1 ratio of tip diameter to shaft diameter) instruments such as ice picks and the like. Of these measures of performance, one of the most difficult to achieve is resistance to puncture, particularly by sharp instruments.
Varied approaches have heretofore been utilized to provide the requisite protection. For example, U.S. Pat. No. 5,185,195 teaches the use of a number of layers of fabric secured together by closely spaced rows of stitching. Overlapping ceramic disks are also optionally incorporated into the vestment.
U.S. Pat. No. 4,737,401 teaches formation of a ballistic resistant fabric from high molecular weight fibers of polyolefin, polyvinyl alcohol, and polyacrylonitrile materials. The fibers may additionally be coated. U.S. Pat. No. 4,574,105 teaches the use of both polyester (p-phenylene terepthalamide) yarns and polyamide yarns. U.S. Pat. No. 5,225,241 teaches the enhancement to ballistic penetration by forming a vestment from coated fibers.
Because of the extreme demands made on the materials, they are frequently expensive to produce, both in fabric and in finished form. In addition, processes used to form the fabric and the finished article frequently result in a fabric and an article which is relatively stiff and not readily drapable. Accordingly, the user frequently finds such vestments unduly restrictive and uncomfortable, and often dispenses with their use in situations where good safety practices would otherwise call for them.